My 4hp Johnson seahorse is loosing power

bozza_boatie

Seaman
Joined
Apr 13, 2003
Messages
65
My 4hp Johnson seahorse wich is a late eighties model has been raning well for the last couple of years. But now i start it up in nutural and it runs fine but when i put it in gear it revs down and looses power. I put it on full blast and it goes a 1/3 as fast as it used to.<br /><br />What is the problem and how can i fix it . Any sugestions will help. Thank you.
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: My 4hp Johnson seahorse is loosing power

Bozza,<br />Things to check:<br />Compression on both cylinders. <br />Check to see if you have spark to both cylinders, perhaps you're loosing one cylinder.<br />Check sync and link at carb linkage.<br />Check carb for debris, clogged jets, float level. Clean carb (rebuild as necessary)<br />Will the motor rpm's increase if you squeeze the primer bulb?? Try spraying fuel mix into carb throat when it's running at 1/3 speed to see if motor rpm's increase.
 

bozza_boatie

Seaman
Joined
Apr 13, 2003
Messages
65
Re: My 4hp Johnson seahorse is loosing power

One more thing my motor has this dial to change the fuel from lean to rich which is the best for running the motor?
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: My 4hp Johnson seahorse is loosing power

OK, here's the carb adjustments:<br /><br />(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<br /><br />Initial setting is: Slow speed = seat gently, then open 1-1/2 turns. (All carbs at the<br />same time)<br /><br />(On the following adjustment, finish one carb before going on to the next one, then<br />double check the adjustments).<br /><br />Start engine and set the rpms to where it just stays running. In segments of 1/8<br />turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to<br />respond. As you turn the valve in, the rpms will increase. Lower the rpms again to<br />where the engine will just stay running.<br /><br />Eventually you'll hit the point where the engine wants to die out or it will spit back<br />(sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4<br />turn, you'll find the smoothest slow speed setting.<br /><br />When you have finished the above adjustment, you will have no reason to move<br />them again unless the carburetor fouls/gums up from sitting, in which case you<br />would be required to remove, clean, and rebuild the carburetor anyway.<br /><br />You really should consider picking up a manual for your motor. I know it's been said a thousand times here on other posts, but , it's an essential part of owning a motor.<br /><br />BTW: Kudos to Joe Reeves for the above info!! :D
 
Top